1. Field of the Invention
The present invention relates to cooperative relaying in a multi-hop relay network. More particularly, the present invention relates to a method and system for cooperative relaying in a multi-hop relay network wherein a Mobile Station (MS) can enhance reception performance by receiving and decoding signals from both a relay link of a Base Station (BS) and an access link of a Relay Station (RS).
2. Description of the Related Art
In next generation mobile communications, Relay Stations (RSs) will be deployed to cover heterogeneous service areas rather than Base Stations (BSs). The RSs may contribute to coverage area extension and capacity enlargement. Unlike analog and digital repeaters employed in existing cellular systems, relay systems enable radio resource management in consideration of situations related to interference and resources. This makes it possible to secure better links for capacity enhancement, and to provide acceptable services to mobile stations located in shadow areas for coverage extension.
To enhance reception performance of mobile stations in relay networks, cooperative relaying, where RSs and BSs cooperate for transmissions, has been proposed. Cooperative relaying has been adopted by the IEEE 802.16j standard.
In existing schemes for cooperative relaying, for access link transmission at the second hop, a BS performs simultaneous transmission to enhance reception performance of a Mobile Station (MS). However, although the MS may receive a signal of an acceptable level from the BS, the MS may not utilize information of a relay link signal at the first hop. Further, in a network having multiple RSs, to provide a cooperative relay service to multiple RSs or multiple MSs, the BS may have to utilize separate resources, excluding resource reuse gain.
Accordingly, it is necessary to develop a scheme for cooperative relaying that utilizes both a relay link signal at a first hop and an access link signal at a second hop.